Compact PIFA Antenna

ABSTRACT

Various planar inverted-F antenna configurations may include an antenna element formed on the top of a PCB and a ground element formed on the bottom of the PCB. Two or more slots may be included in the antenna element for reducing the antenna area while maintaining a suitable impedance bandwidth. A slot may be included in the ground element for reducing the ground area while increasing radiation efficiency. A folded ground may be formed on the top of the PCB for reducing system area while maintaining suitable performance. By moving the folded ground closer to the antenna element and increasing the PCB thickness, significant reductions in system area may be achieved, while maintaining or improving performance in terms of radiation pattern, radiation efficiency and impedance bandwidth.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present disclosure is related to U.S. non-provisional patentapplication DWV-3DPF-010 entitled “Methodology for Pocket-forming”;DWV-3DPF-027 entitled “Receivers for Wireless Power Transmission”;DWV-3DPF-029 entitled “Transmitters for Wireless Power Transmission,”which are each invented by Michael Leabman, and the entirety of whichare incorporated herein by reference.

BACKGROUND

1. Field of the Disclosure

The present disclosure relates in general to antennas, and morespecifically, to compact planar inverted-F antennas (PIFAs) that can beintegrated into receivers for wireless power transmission.

2. Background Information

Wireless power transmission may include a transmitter for forming anddirecting RF waves towards a receiver which may convert RF waves orpockets of energy into usable power for charging or powering anelectronic device. The receiver may be integrated into the electronicdevice (i.e. a smartphone, a tablet) or may be in the form of a casethat can be operatively coupled with the electronic device for suitablecharging or powering. The receiver may include an antenna array with aplurality of antenna elements configured as will be described.

One important factor considered in wireless power transmission is thecontinuous improvement of the antenna elements used in the receiver.This is becoming more relevant as the trend of smaller hand heldelectronic devices with an increasing number of wireless functions maysignificantly complicate the antenna selection and integration process.As such, it may be desirable to decrease the size of antenna elements sothat these antenna elements can be easily incorporated into the receiveror electronic device, while sustaining or improving their performance.It may be also desirable to have antenna elements with robust mechanicalproperties for long lasting integration and operation.

SUMMARY

Various embodiments of PIFAs described herein may include an antennaelement with two or more slots formed over the top layer of a printedcircuit board (PCB), where these antenna slots may be designed forreducing the area of the antenna while keeping a suitable impedancebandwidth. These PIFA configurations may also include a ground elementformed on the bottom layer of the PCB and operatively coupled with theantenna element through ground and signal vias. The ground element mayalso include one or more slots designed for reducing the area of theground while increasing the radiation efficiency of the PIFA system. Theground element may also have a large part of its central area missing,provided its perimeter is electrically connected. This may furtherincrease radiation efficiency, and may also allow for other systems tobe inserted within that region. The missing central ground area may notsignificantly affect the antenna operation, except possibly in de-tuningthe impedance bandwidth, which can be adjusted by the antenna elementitself.

In one embodiment, a PIFA configuration may include a folded groundformed over the empty space of a PCB top layer, without interfering withthe operation of an antenna element which may be also formed over thePCB top layer. This folded ground may be operatively connected with aground element on the PCB bottom layer through folded ground vias. Anobject of this folded ground may be to allow the reduction in the systemarea while maintaining an omnidirectional radiation pattern and asuitable performance in terms of impedance bandwidth and radiationefficiency.

In another embodiment, a PIFA configuration may include a folded groundextended or moved closer to an antenna element formed over the top layerof a PCB. By moving the folded ground closer to the antenna element andslightly increasing the PCB thickness, the PIFA system may achievesignificant reductions in the system area, while maintaining anomnidirectional radiation pattern and improving performance in terms ofimpedance bandwidth and radiation efficiency.

In yet another embodiment, a PIFA configuration may include a foldedground formed over the top layer of a PCB, where this folded ground maybe at its maximum allowable distance from an antenna element. Thismaximum folding may allow the system area to be greatly reduced, whilemaintaining a suitable performance in terms of impedance bandwidth,radiation pattern, and efficiency.

The PIFA configurations described herein may be implemented in amonolithic form factor for complete integration into a single, doublelayer, printed circuit board (PCB) of compact dimensions. These PIFAconfigurations may also be embedded into larger PCBs, for example areceiver PCB or an electronic device PCB. The omnidirectional radiationpattern of the disclosed PIFA configurations may allow ad-hoc placementinto a receiver or electronic device. Moreover, the disclosed PIFAconfigurations may achieve compact dimensions while maintaining suitableperformance for wireless power transmission.

Additional features and advantages may become apparent in view of thedetailed descriptions which follow, taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure can be better understood by referring to thefollowing figures. The components in the figures are not necessarily toscale, emphasis instead being placed upon illustrating the principles ofthe disclosure. In the figures, reference numerals designatecorresponding parts throughout the different views.

FIG. 1 illustrates a three-dimensional (3-D) view of a planar inverted-Fantenna integrated in a printed circuit board (PCB).

FIG. 2A shows an omnidirectional 3-D radiation pattern of the PIFA ofFIG. 1 oriented as shown in FIG. 1.

FIG. 2B depicts the return loss of the PIFA shown in FIG. 1 when fed bya 50-Ohm port.

FIG. 3 depicts a 3-D view of a PIFA with a folded ground.

FIG. 4A shows an omnidirectional 3-D radiation pattern of the PIFA ofFIG. 3 as oriented in FIG. 3.

FIG. 4B illustrates the return loss of the PIFA shown in FIG. 3 when fedby a 50-Ohm port.

FIG. 5 shows a 3-D view of a PIFA with a folded ground moved closer toan antenna element.

FIG. 6 depicts the return loss of the PIFA shown in FIG. 5 when fed by a50-Ohm port.

FIG. 7 shows a 3-D view of a PIFA with folded ground moved at a maximumallowable distance from an antenna element.

FIG. 8 illustrates the return loss of the PIFA shown in FIG. 7 when fedby a 50-Ohm port.

DETAILED DESCRIPTION

The present disclosure is here described in detail with reference toembodiments illustrated in the drawings, which form a part here. Otherembodiments may be used and/or other changes may be made withoutdeparting from the spirit or scope of the present disclosure. Theillustrative embodiments described in the detailed description are notmeant to be limiting of the subject matter presented here.

DEFINITIONS

As used here, the following terms may have the following definitions:

“Wireless Power Transmission” may refer to the action of a transmittercapable of pocket forming for generating pockets of energy that may beutilized by a receiver for charging or powering an electronic device.

“Pocket-forming” may refer to generating two or more RF waves whichconverge in 3-d space, forming controlled constructive and destructiveinterference patterns.

“Pockets of energy” may refer to areas or regions of space where energyor power may accumulate in the form of constructive interferencepatterns of RF waves.

“Null-space” may refer to areas or regions of space where pockets ofenergy do not form because of destructive interference patterns of RFwaves.

“Transmitter” may refer to a device, including a chip which may generatetwo or more RF signals, at least one RF signal being phase shifted andgain adjusted with respect to other RF signals, substantially all ofwhich pass through one or more RF antennas such that focused RF signalsare directed to a target.

“Receiver” may refer to a device including at least one antenna element,at least one rectifying circuit, and at least one power converter, whichmay utilize pockets of energy for powering or charging an electronicdevice.

DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a three-dimensional (3-D) view of a planar inverted-Fantenna (PIFA) 100 integrated in a printed circuit board (PCB) 102. ThisPIFA 100 may be designed to be as small as possible while maintaining asuitable performance for wireless power transmission, and it may beintegrated in a double layer PCB for achieving a monolithic form. In oneembodiment, PIFA 100 may be formed on the PCB of an electronic devicesuch as a smartphone, tablet, a laptop computer, a PDA, and the like. Inanother embodiment, PIFA 100 may be formed on the PCB of a receiver thatmay be used for wireless power transmission. Yet in another embodiment,PIFA 100 may be formed on its own PCB which may be connected to the PCBof an electronic device or a receiver.

PIFA 100 may include an antenna element 104 formed over the top layer ofPCB 102, and a ground element 106 formed over the bottom layer of PCB102. Both PCB layers may be made of suitable metals such as copper ofsmall metal thickness relative to the total PCB 102 thickness. PCB 102may include a dielectric base with a suitable dielectric constant. Inone embodiment, an Isola FR408HRIS may be used for PCB 102 materials.

Antenna element 104 may include two slots 108 designed for reducing thearea of antenna element 104 while maintaining a suitable bandwidthoperation. For example, PIFA 100 may achieve a bandwidth of about 160MHz. Without the two slots 108, PIFA 100 may still be able to achieve asimilar bandwidth, but the area of antenna element 104 may have to beincreased about 34%. More slots may be introduced on antenna element 104for even further area reduction if necessary, according to application.

Similarly to antenna element 104, ground element 106 may include a slot110 the main purpose of which may be to reduce the area of the groundelement 106 while reducing losses and increasing radiation efficiency.For example, by including slot 110, PIFA 100 may achieve a radiationefficiency of about 69%. In one embodiment, slot 110 in ground element106 may increase the radiation efficiency of PIFA 100 by about 22% andabout 32% for PCB 102 substrates having a thickness of about 1.4 mm andabout 0.8 mm, respectively. In another embodiment, the combination ofground slot 110 and ground element 106 missing central area may increasethe radiation efficiency by about 32% and about 54% for 1.4 mm-thick and0.8 mm-thick PCB 102 substrates, respectively, relative to designs withsolid ground.

PIFA 100 may also include a signal via 112, a ground via 114, and a RFport 116 for electrical connection purposes. In one embodiment, asemi-rigid 50 Ohm coax cable can be connected to RF port 116 forprototype measurements. For integration purposes, PIFA 100 may be fedthrough RF port 116 by a transmission line integrated in a larger PCB.

In an embodiment, dimensions of PIFA 100 may be about 12 mm, 3.5 mm, and1.4 mm in the x-axis, y-axis, and z-axis respectively, for an estimatedsystem area of about 42 mm² and a system volume of about 58.8 mm³.

FIGS. 2A and 2B show the performance 200 of PIFA 100 according toembodiments described herein.

FIG. 2A shows an omnidirectional 3-D radiation pattern of PIFA 100oriented as shown in FIG. 1. This omnidirectional radiation pattern inFIG. 2A may be similar to radiation patterns exhibited in dipoleantennas, thereby allowing flexible placement or integration of PIFA 100into larger form factors, for example, a receiver PCB or an electronicdevice PCB. In one embodiment, PIFA 100 may exhibit a maximum gain ofabout −0.0099 dBi at 5.8 GHz.

FIG. 2B illustrates the return loss of PIFA 100 when fed by a 50-Ohmport. As seen from probes m1 and m2, PIFA 100 may exhibit an impedancebandwidth of about 160 MHz at −10 dB, where this bandwidth may providesufficient margins for possible detuning upon integration of PIFA 100into an electronic device or a larger PCB. Radiation efficiency of PIFA100 may be around 69% at 5.8 GHz.

Although PIFA 100 may exhibit suitable characteristics for wirelesspower transmission, it may be an object of the following embodiments toprovide PIFAs with a similar monolithic PCB form factor, but with areduced size and a similar or improved performance in terms of impedancebandwidth, radiation pattern, and maximum radiation efficiency.

FIG. 3 is a 3-D view of a PIFA 300 with a folded ground 302, accordingto embodiments. This PIFA 300 may be designed to be as small as possiblewhile maintaining a suitable performance for wireless powertransmission, and it may be integrated in a double layer PCB forachieving a monolithic form. In one embodiment, PIFA 300 may be formedon the PCB of an electronic device such as a smartphone, tablet, alaptop computer, a PDA, and the like. In another embodiment, PIFA 300may be formed on the PCB of a receiver that may be used for wirelesspower transmission. Yet in another embodiment, PIFA 300 may be formed onits own PCB which may be connected to the PCB of an electronic device ora receiver.

Similarly to PIFA 100, PIFA 300 in FIG. 3 may include PCB 102, antennaelement 104, ground element 106, antenna slots 108, ground slot 110,signal via 112 and ground via 114. However, unlike PIFA 100, PIFA 300may include folded ground 302 which can be formed over an empty regionof the top layer of PCB 102 without interfering with the performance ofantenna element 104. Folded ground 302 can be raised over the top layerof PCB 102 and can be connected to ground element 106 through foldedground vias 304 which may not significantly affect the performance ofPIFA 300. Folded ground 302 may act as an extension of ground element106.

According to some aspects of this embodiment, folded ground 302 mayallow the dimensions of PIFA 300 to be reduced compared to thedimensions of PIFA 100, while improving or at least maintaining similarperformance characteristics. For example, PIFA 300 dimensions in thex-axis, y-axis, and z-axis may be about 10 mm, 3.3 mm, and 1.4 mmrespectively, for a system area of about 33 mm² and a system volume ofabout 46.2 mm³. This can be translated to a 21% reduction in system areaand volume as compared to PIFA 100.

FIGS. 4A and 4B show the performance 400 of PIFA 300 according toembodiments described herein. Performance 400 of PIFA 300 may be fairlysimilar to performance 200 of PIFA 100, but significant reductions insize may be achieved as previously stated.

FIG. 4A shows an omnidirectional 3-D radiation pattern of PIFA 300oriented as shown in FIG. 3. As seen in FIG. 4A, PIFA 300 may stillexhibit a suitable omnidirectional radiation pattern which may allow aflexible placement or integration of PIFA 300 into larger form factors,for example, a receiver PCB or an electronic device PCB. In oneembodiment, PIFA 300 may exhibit a maximum gain of about −0.078 dBi at5.8 GHz.

FIG. 4B illustrates the return loss of PIFA 300 when fed by a 50-Ohmport. As seen from probes m1 and m2, PIFA 300 may exhibit an impedancebandwidth of about 140 MHz at about −10 dB which may be slightly lowerthan the impedance bandwidth of PIFA 100, but it may still be able toprovide sufficient margins for possible detuning upon integration ofPIFA 300 into an electronic device or a larger PCB form. PIFA 300 mayexhibit a radiation efficiency of about 62% which may be slightly lowerthan the radiation efficiency exhibited by PIFA 100, but it may be stillsuitable for effective wireless power transmission.

FIG. 5 illustrates a 3-D view of a PIFA 500 with folded ground 302extended closer to antenna element 104, according to embodiments of thepresent invention. This PIFA 500 may be designed to be as small aspossible while improving or at least maintaining a suitable performancefor wireless power transmission. PIFA 500 may be integrated in a doublelayer PCB for achieving a monolithic form. In one embodiment, PIFA 500may be formed on the PCB of an electronic device such as a smartphone,tablet, a laptop computer, a PDA, and the like. In another embodiment,PIFA 500 may be formed on the PCB of a receiver that may be used forwireless power transmission. In yet another embodiment, PIFA 500 may beformed on its own PCB which may be connected to the PCB of an electronicdevice or a receiver.

Similarly to PIFA 300, PIFA 500 may include PCB 102, antenna element104, ground element 106, antenna slots 108, ground slot 110, signal via112, ground via 114, folded ground 302, and folded ground vias 304.However, compared to PIFA 300, folded ground 302 in PIFA 500 may bemoved closer to antenna element 104 as seen in FIG. 5. In addition, thethickness of PIFA 500 may be increased from about 1.4 mm to about 2.4mm. PIFA 500 dimensions in the x-axis, y-axis, and z-axis may be about10 mm, 2.4 mm, and 2.4 mm respectively, for a system area of about 24mm² and a system volume of about 57.6 mm³.

According to some aspects of this embodiment, by extending folded ground302 towards antenna element 104, the system area of PIFA 500 can bereduced about 27% and 43% compared to PIFA 300 and PIFA 100respectively. Moreover, by combining this extended folded ground 302with a slightly thicker PCB, the overall performance of PIFA 500 may besignificantly improved. For example, PIFA 500 may achieve a radiationefficiency of about 82% at 5.8 GHz compared to about 69% in PIFA 100 and62% in PIFA 300.

FIG. 6 shows the performance 600 of PIFA 500 according to embodimentsdescribed herein. Compared to PIFA 100 and PIFA 300, the performance ofPIFA 500 may be significantly improved, while also achieving significantreductions in system area as previously stated.

In addition to a higher radiation efficiency, the return loss of PIFA500 when fed by a 50-Ohm port, as shown in FIG. 6, may exhibit a higherimpedance bandwidth of about 180 MHz at −10 dB, compared to 160 MHz and140 MHz for PIFA 100 and PIFA 300 respectively. This bandwidth mayprovide sufficient margins for possible detuning upon integration ofPIFA 500 into an electronic device or a larger PCB form factor.

As in PIFA 100 and PIFA 300, PIFA 500 may still exhibit anomnidirectional radiation pattern (not shown in FIG. 6) for allowingflexible placement or integration of PIFA 500 into larger form factors,for example, a receiver PCB or an electronic device PCB. In oneembodiment, PIFA 500 may exhibit a gain of about +0.55 dBi at 5.8 GHz.

FIG. 7 shows a 3-D view of a PIFA 700 where folded ground 302 can beextended even closer to antenna element 104, according to embodiments ofthe present invention. This PIFA 700 may be designed to be as small aspossible while improving or at least maintaining a suitable performancefor wireless power transmission. PIFA 700 may be integrated in a doublelayer PCB for achieving a monolithic form. In one embodiment, PIFA 700may be formed on the PCB of an electronic device such as a smartphone,tablet, a laptop computer, a PDA, and the like. In another embodiment,PIFA 700 may be formed on the PCB of a receiver that may be used forwireless power transmission. Yet in another embodiment, PIFA 700 may beformed on its own PCB which may be connected to the PCB of an electronicdevice or a receiver.

Similarly as in PIFA 300 and PIFA 500, PIFA 700 may include PCB 102,antenna element 104, ground element 106, antenna slots 108, ground slot110, signal via 112, ground via 114, folded ground 302, and foldedground vias 304. However, as seen in FIG. 7, folded ground 302 can bemoved even closer to antenna element 104 as compared to PIFA 500 andPIFA 300. In an embodiment, the thickness of PIFA 700 may be about 2.4mm. Overall PIFA 700 dimensions in the x-axis, y-axis, and z-axis may beabout 9 mm, 2.4 mm, and 2.4 mm respectively, for a system area of about21.6 mm² and a system volume of about 51.8 mm³.

According to some aspects of this embodiment, by extending folded ground302 even closer to antenna element 104 as compared to PIFA 500, thesystem area and volume area of PIFA 700 may be reduced about 10% more,while maintaining a similar performance. For example, PIFA 700 mayexhibit a radiation efficiency of about 76%, at 5.8 GHz, just slightlylower than radiation efficiency in PIFA 500, but higher compared to PIFA300 and PIFA 100. In one embodiment, folded ground 302 in PIFA 700 maybe at a maximum allowable distance from antenna element 104 formaintaining a suitable performance for wireless power transmission.

Compared to PIFA 300 and PIFA 100, the system area reductions achievedin PIFA 700 may be significantly higher, about 35% and 49% respectively.Similarly, PIFA 700 may exhibit an enhanced performance in terms ofhigher impedance bandwidth and radiation efficiency as compared withPIFA 300 and PIFA 100.

FIG. 8 shows the performance 800 of PIFA 700 according to embodimentsdescribed herein. Compared to PIFA 100, PIFA 300, and PIFA 500,performance of PIFA 700 may be maintained fairly similar and in somecases, it may be enhanced; all of this while achieving significantreductions in system area.

The return loss of PIFA 700 when fed by a 50-Ohm port, as shown in FIG.8, may exhibit an impedance bandwidth of about 180 MHz at −10 dB, whichis about the same bandwidth exhibited by PIFA 500, but higher comparedto 160 MHz and 140 MHz for PIFA 100 and PIFA 300 respectively. Thisbandwidth may provide sufficient margins for possible detuning uponintegration of PIFA 700 into an electronic device or a larger PCB formfactor.

PIFA 700 may still exhibit an omnidirectional radiation pattern (notshown in FIG. 8) for allowing flexible placement or integration of PIFA700 into larger form factors, for example, a receiver PCB or aelectronic device PCB. In one embodiment, PIFA 700 may exhibit a maximumgain of about +0.019 dBi at 5.8 GHz.

In general, folded ground 302 in PIFA 300, PIFA 500, and PIFA 700 mayallow significant reductions in the system area compared to the priorart. And by combining folded ground 302 with a slightly thicker PCB, theperformance in PIFA 500 and PIFA 700 may be improved even more.

It may be apparent to someone skilled in art that the selection of theoptimal PIFA configuration may depend on the characteristics and formfactor of a particular receiver or electronic device. For example,optimal configurations may be selected based on criteria of having aPIFA with the smallest system area; the higher impedance bandwidth; thehigher radiation efficiency; the smallest system volume; or acombination of criteria as required by the application.

The preceding description of the disclosed embodiments is provided toenable persons skilled in the art to make or use the present invention.Various modifications to these embodiments may be readily apparent tothose skilled in the art, and the generic principles defined herein maybe applied to other embodiments without departing from the spirit orscope of the invention. Thus, the present invention is not intended tobe limited to the embodiments shown herein but is to be accorded thewidest scope consistent with the following claims and the principles andnovel features disclosed herein.

What is claimed is:
 1. A planar inverted-F antenna (PIFA), comprising: aprinted circuit board (PCB) formed of an electrically insulatingmaterial with a low electrical conductivity, the PCB having a topsurface and a bottom surface, and a thickness defined by a shortestdistance between the top surface and the bottom surface; an antennaelement formed of an electrically conducting material with an electricalconductivity higher than that of the PCB, the antenna element disposedon the top surface of the PCB, the antenna element having apredetermined impedance bandwidth and a plurality of slots arranged toprovide the antenna element with a surface area smaller than a surfacearea of an antenna element having the same impedance bandwidth but nothaving a plurality of slots, all other parameters relevant to theimpedance bandwidth being equal; a ground element formed of anelectrically conducting material with an electrical conductivity higherthan that of the PCB, the ground element disposed on the bottom surfaceof the PCB and operatively coupled to the antenna element, the groundelement having a continuous perimeter defining a central area at least aportion of which comprises a layer formed of the electrically conductingmaterial that is substantially continuous, the layer having at least oneinternal slot arranged to provide the ground element with a layersmaller than a layer of a ground element providing the same radiationefficiency but not having at least one internal slot, all otherparameters relevant to the radiation efficiency being equal.
 2. The PIFAof claim 1, wherein the ground element is operatively coupled to theantenna element through a ground via and a signal via each defined by arespective hole through the PCB.
 3. The PIFA of claim 1, wherein theground element perimeter encloses a portion of the central area thatdoes not comprise a substantially continuous layer formed of theelectrically conducting material.
 4. The PIFA of claim 1, wherein theground element comprises a folded portion that extends from the bottomto the top of the PCB and toward the antenna element.
 5. The PIFA ofclaim 4, wherein the portion of the ground element on the top of the PCBis operatively coupled to the portion of the ground element on thebottom of the PCB through folded ground vias each defined by arespective hole through the PCB.
 6. The PIFA of claim 5, wherein: theantenna element is disposed substantially directly above thesubstantially continuous portion of the ground element; the portion ofthe ground element disposed on the top surface of the PCB is disposedsubstantially directly above a corresponding portion of the groundelement disposed on the bottom surface of the PCB; and an area definedby the perimeter of the ground element viewed from a point on a linethrough the center of the ground element and normal to one of thesurfaces of the PCB, is smaller than a corresponding area of a PIFAproviding substantially similar radiation pattern, impedance bandwidth,and radiation efficiency, but having a ground element that does notinclude a folded portion.
 7. The PIFA of claim 6, wherein the thicknessof the PCB is greater than a corresponding thickness of the PIFA thatdoes not include a folded portion.
 8. The PIFA of claim 1, wherein thedistance between the antenna element and the portion of the groundelement disposed on the top of the PCB, and the thickness of the PCB,are both configured to minimize the area defined by the ground elementwhile providing at least a predetermined radiation pattern, impedancebandwidth, and radiation efficiency.
 9. The PIFA of claim 1, wherein thePIFA presents a monolithic form factor on a single double layer PCB. 10.The PIFA of claim 9, wherein the PCB is dedicated to the PIFA andconfigured to be connected to the PCB of an electronic device.
 11. ThePIFA of claim 9, wherein the PCB is physically coupled to at least oneelement of an apparatus that does not form part of the PIFA.
 12. ThePIFA of claim 9, wherein the PIFA is incorporated into an electronicdevice.
 13. The PIFA of claim 12, wherein the electronic device is oneof a receiver, a smartphone, a tablet computer, a laptop computer, and apersonal digital assistant (PDA).
 14. The PIFA of claim 12, wherein theelectronic device provides wireless power transmission.
 15. The PIFA ofclaim 1, wherein the PIFA during operation provides a radiation patternthat is substantially omnidirectional.
 16. The PIFA of claim 1, whereinthe PIFA during operation provides sufficient margins for possibledetuning upon integration into an electronic device.
 17. The PIFA ofclaim 1, wherein the PIFA provides a gain at 5.8 GHz of between about−0.078 dBi and +0.55 dBi.
 18. The PIFA of claim 1, wherein the PIFAexhibits an impedance bandwidth at 5.8 GHz and −10 dB of between about140 MHz and 180 MHz.
 19. The PIFA of claim 1, wherein the PIFA exhibitsa radiation efficiency at 5.8 GHz of between about 62% and 82%.
 20. ThePIFA of claim 1, wherein the PCB thickness is one of 0.8 mm, 1.4 mm, and2.4 mm, the width of the PIFA is between about 2.4 mm and 3.5 mm, andthe length of the PIFA is between about 9 mm and 12 mm.
 21. The PIFA ofclaim 1, wherein operation in other desired frequency bands may beobtained by suitably scaling the dimensions of antenna, antenna slots,ground, ground slot, PCB insulating material permittivity and PCBthickness.